Spinal Muscular Atrophy (SMA) is one of the most devastating neurological diseases of childhood. Affected infants and children suffer from progressive muscle weakness caused by degeneration of lower motor neurons in the spinal cord and brainstem. Clinically, four phenotypes are distinguished within the continuous spectrum of disease severity based on the age of onset and the highest motor milestone ever achieved. SMA is caused by homozygous deletion of the survival motor neuron-1 (SMN1) gene. A related gene, SMN2, produces low levels of full-length SMN protein due to inefficient splicing. There is an inverse correlation between SMN copy number and disease severity, presumably mediated by levels of full length SMN protein. Therefore, increasing the amount of full-length SMN protein is a promising treatment strategy. Several drugs targeting splicing efficiency have resulted in increased SMN protein in preclinical assays and are now awaiting clinical testing.